Thin-layer chromatography: Direct bioautography as a method of examination of antimicrobial activity of selected Potentilla species

ABSTRACT

Simple method for preparing biologically active material from plant extract may consist of four steps: obtaining an extract from selected plant, analytical chromatography with biological detection and transition to preparative scale, preparative isolation of biologically identified bands/groups of bands from chromatogram, rechromatography of isolated fractions. The next step of proceeding may be a quality analysis of separated material by, e.g., thin-layer chromatography (TLC)-MS Interface or biological studies after isolation. Extracts obtained from four Potentilla species: P. erecta, P. collina, P. megalantha, and P. crantzi were separated on silica plates, developed with the nonaqueous eluent. Immersion—direct bioautography was chosen as a method of detection of bands’ activity for their selection for isolated bands. Antibacterial/bacteriostatic properties of marked areas was the preliminary criterion of choice the samples to the further examinations. Preparative thin layer chromatography allowed isolation of various number of fractions of each extracts. Obtained fractions were examined in various TLC systems (silica/nonaqueous mixture of solvents) with the various modes of development to obtain the best separation effect. The next step was a once more bioautographic detection of separated fractions on the TLC plates. The found chromatographic systems will be used to mass spectrometric determination of biologically active compounds contained in examined extracts. Bioautographic indication will be the method of choice for subsequently isolated compounds or groups of compounds.

KEYWORDS:

• Bioautography
• P. collina
• P. crantzi
• P. megalantha
• Potentilla erecta
• preparative TLC